The present invention relates to a series of novel phosphate ester derivatives containing a cyclic ether system and provides processes for producing these compounds and compositions containing them for use as anti-cancer agents.
Many compounds have been shown to have anti-tumor activity, but the number of compounds available for practical, therapeutic use is relatively small. The problem is that the majority of compounds which have therapeutic effects against tumor cells are also toxic to normal tissues for various reasons. For example, it is known that 3-O-alkyl lysoglycerophospholipid derivatives shown an anti-cancer effect and, e.g., UK Patent Specification No. 1,583,661 discloses a compound of formula: ##STR3## However, compounds of this type have an activity similar to that of platelet activating factor (hereinafter abbreviated to "PAF"), for example platelet-aggregation and hypotensive activities. These unwanted activities render the 3-O-alkyl lysoglycerophospholipid derivatives extremely toxic.
European Patent Publication No. 103,877 discloses a series of phosphate derivatives which are said to have anti-tumor activity, but these are derivatives of sugars, which are conceptually and structurally very different from the compounds of the present invention.